    //定义懒加载插件
    import { useIntersectionObserver } from "@vueuse/core";

    export const lazyPlugin = {
        install(app) {
            //懒加载指令逻辑
            app.directive('img-lazy', {
                mounted(el, binding) {
                    // el: 指令绑定的那个元素 img
                    // binding: binding.value  指令等于号后面绑定的表达式的值  图片url
                    // console.log(el,binding);
                    const { stop } = useIntersectionObserver(
                        el,
                        ([{ isIntersecting }]) => {
                        // console.log(isIntersecting)
                        if (isIntersecting) {
                            // 进入视口区域
                            el.src = binding.value
                            stop()
                        }
                        },
                    )
                },
            })
        }
    }